The next time you cross the Mackinac Bridge, divide your $1.50 toll money into two piles. Put four quarters into one pile to pay for the cost of operating the bridge. Put the other two quarters into a second pile for repainting the bridge with lead-free paint. Now, do this each time you cross the bridge for the next 21 years.

Here's the story behind this: For nearly 30 years after the Mackinac Bridge was completed in 1957, it was painted with a lead-based paint. Every nine years or so it was sandblasted and repainted. However, more recent guidelines from the federal Environmental Protection Agency (EPA) dictate which paints can be used and how they must be removed. To comply, the Mackinac Bridge Authority will soon begin removing the bridge's paint by a process called enclosure, whereby the structure is cleaned within a tent-like covering to keep paint chips from falling into the water or blowing onto populated areas.

The cost of enclosure is staggering: nearly $50 million, which the Authority wants to pay for by budgeting $2.2 million each year for the next 21 years. Since a little more than four million vehicles cross the Mackinac Bridge annually, each vehicle would pay about 50 cents more if the cost were spread evenly. On June 1, however, the tolls on trucks almost doubled, partly because of the EPA order. Trucks are only about 5 percent of the bridge traffic, however, so cars may soon be paying more too.

Unfortunately, this enclosure scheme is a huge waste of money.

No one has ever documented any harm caused by paint chips falling off the Mackinac Bridge. The greater risk, in fact, may be from workers inhaling paint particles or having accidents during the enclosure process. The Michigan Department of Natural Resources (DNR) has rolled over for the EPA rather than resist this unfunded federal mandate.

Enclosure could be very dangerous to the workers and is not likely to be worth the effort, says Sanford Weiner, a research associate at the Center for International Studies at the Massachusetts Institute of Technology. For Michigan to embark on this without so much as a study of the costs and benefits, as well as the risks, is foolish.

Others agree. It's flirting with death, said State Senator Walter North, a former chief executive of the Mackinac Bridge Authority. We have strong Michigan winds that could hit that tent, break it apart, and kill someone in a passing car. That's why I always said no to enclosure when I was in charge.

The irony here is that the expenses and risks of enclosure are being undertaken after most of the environmental damage from lead has been removed. The federal Department of Health and Human Services reports a sevenfold drop in the national levels of lead in human blood in the last 25 years. The switch to lead-free gas and aluminum cans (in place of tin cans, which often contained lead) helps explain this drop. According to the EPA's own data, the air we breathe today in the U.S. is 20 times freer of lead than it was in 1970. Furthermore, Lakes Michigan and Huron are up to four times cleaner than they were 25 years ago. In any case, most of the lead-paint problem was from lead paint inside buildings, not outside, and especially not from bridges.

Enclosure is not only dubious science, it's bad economics as well.

The extra toll will increase the costs of doing business in the Upper Peninsula. Tourism, hunting, logging, and other enterprises will suffer, which won't help the struggling economies of northern Michigan counties. If it weren't for this wasteful repainting scheme, we could actually cut tolls rather than raise them; in a typical year, the bridge runs a surplus of about a million dollars after all operating and maintenance costs are accounted for.

Using automated toll booths on the bridge instead of toll collectors could save a minimum of $500,000 each year, according to officials in the Michigan Department of Transportation. That would further support the case for lower, not higher, tolls-except that now, the Bridge Authority would probably want to apply such savings to the cost of meeting EPA's unpredictable mandates.

For the next 21 years, unless pressure is brought to bear on the EPA, we will be risking lives and spending almost $50 million with little to show for it. The bridge will not necessarily be better or safer. Little if any environmental gain will result. Counties that need traffic will lose some and tourists will have less to spend. But the bureaucrats in Washington will rest more easily knowing that their latest guidelines have been met.